diff --git a/src/brep/step_import.cpp b/src/brep/step_import.cpp
index 4bebf38..54555c8 100644
--- a/src/brep/step_import.cpp
+++ b/src/brep/step_import.cpp
@@ -1264,7 +1264,10 @@ private:
         }
 
         const auto& ent = entities_.at(ref);
-        curves::NurbsSurface ns;
+        // Default-construct with a dummy surface (NurbsSurface has no default ctor)
+        std::vector<std::vector<Point3D>> g0 = {{Point3D(0,0,0), Point3D(1,0,0)},
+                                                 {Point3D(0,1,0), Point3D(1,1,0)}};
+        curves::NurbsSurface ns(g0, {0,0,1,1}, {0,0,1,1}, {}, 1, 1);
         try {
             if (ent.type == "PLANE")
                 ns = build_plane_surface(ref);